JPS62119302A - Turbine plant with feedwater-heater drain injector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a feedwater heater drain injection device that recovers heat held by the feedwater heater drain in a condensate system of a turbine plant to improve the thermal efficiency of the plant. The present invention relates to a turbine plant having a turbine plant.

[Technical background of the invention and its problems 1 As is well known, in a so-called regeneration cycle type turbine plant in which condensate or feed water sent to a nuclear reactor or boiler is heated by steam extracted from a steam turbine, a feed water heater is used. is an indispensable piece of equipment. In addition to the above-mentioned oil and air, this feedwater heater is led to high-temperature fluid, that is, drain, which is condensed by heat exchange with condensate or feedwater in the upper stage of the feedwater heater, in order to heat the condensate or feedwater. These are configured to be heated sequentially by drain and steam. The heating of condensate or feedwater by such feedwater heaters is roughly divided into high-pressure systems and low-pressure systems depending on the extraction steam pressure of the steam turbine, but the feedwater heater drain of each system is heated in the last part of the system. The conventional method was to dispose of the waste in a condenser or the like after collection. but,
In recent years, it has been proposed to recover heat from the feedwater heater drain in a location other than the feedwater heater, which has completed its heat recovery process, and is attracting attention in a movement aimed at further improving thermal efficiency. As an example of this technique, a case where it is applied to a low pressure system will be explained with reference to FIG.

That is, the condensate system extracts condensate from a condenser 1 via a low-pressure condensate pump 2, purifies it through a condensate purification device 3, and then increases the pressure with a high-pressure condensate pump 4 to a feedwater heater (not shown). This system includes a feed water heater drain injection device 5, for example, a drain pump 7 from a drain tank 6 to extract the feed water heater drain, and purify it through a drain purification device 8. A common configuration is to provide a device that injects the condensate into the condensate system after the condensation process. In the figure, reference numeral 9 indicates a drain pipe having a relief valve 10 for releasing drain from the feed water heater to the condenser 1 in case of an abnormal stop of the drain pump 7, and reference numeral 11 indicates a control valve. . Accordingly, the feedwater heater drain, which was conventionally disposed of in the condenser 1, is led into the condensate, so that the heat it possesses is given to the condensate, and effective heat recovery can be achieved.

However, in the above-mentioned feedwater heater drain injection device 5, when the drain pump 7 stops abnormally, the feedwater heater drain is released from the drain tank 6 to the condenser 1. The amount of condensate that must be treated by the water-based condensate purification system @3 will increase significantly. Normally, the processing capacity of the condensate purification device 3 is a nearly constant value per unit time, and an increase in the amount of condensate immediately causes a capacity shortage of the condensate purification device 3, causing the quality of condensate or feed water sent to the reactor etc. to deteriorate. This will result in a decline.

In particular, in nuclear turbine plants, water quality is strictly controlled in order to reduce the amount of radioactive substances inside the reactor, and if a decline in water quality is unavoidable due to insufficient capacity of the condensate purification device 3, the turbine It becomes necessary to limit the output. Therefore, in order to maintain the turbine output, it is possible to increase the capacity of the condensate purification device 3 to compensate for the lack of capacity.

However, since the condensate purification system @ 3 has been greatly improved, abnormal stoppages of the drain pump 7 do not occur very often, so the part with increased capacity is left idle during normal times, which impairs economic efficiency. There is an inconvenience that

[Objective of the Invention 1 The object of the present invention is to provide a feedwater heater drain injection device that can maintain the turbine output in the event of an abnormal stop of the drain pump and at the same time prevent the quality of condensate or feedwater from deteriorating. The purpose of the present invention is to provide a turbine plant having the following features.

[Summary of the invention] The present invention collects condensate generated by heat exchange with condensate in a low-pressure feedwater heater into a drain tank, injects this condensate into condensate flowing through a condensate system via a condensate pump, and In a turbine plant that has a feedwater heater drain injection device configured to release drain from the drain tank to the condenser in case of an abnormal stop of the pump, the condensate is branched from the upstream side of the condensate purification device in the condensate system, and First and second bypass pipes each having a first and second condensate stop valve are provided downstream of the water purification device, and an emergency condensate purification system is provided in the path of the first bypass pipe. This device is equipped with a device that will prevent the drain pump from stopping abnormally.
This system is characterized in that almost all of the increasing amount of condensate is purified through the emergency purification device, and the remaining part is directly led into the condensate without being purified.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to FIG.

In addition, the parts shown in FIG. 2 in the figure are given the same reference numerals, and the explanation thereof will be omitted.

In FIG. 1, the present invention includes first and second bypass pipes 1 that connect the upstream side and the downstream side of the condensate purification device 3, respectively.
2.13, and an emergency condensate purification device 14 and a first condensate stop valve 15 are provided in the path of this first bypass pipe 12.
A second condensation stop valve 16 is disposed within the path of the pipe bus pipe 13 of the power cylinder 2. In addition, condensate purification system @
A flow meter 17 for detecting the flow rate of condensate is provided on the downstream side of 3. In addition to these, the present invention provides υJ constituting the control section.
1!11 equipment 18.19 is provided as follows. That is, when the control ILBM 18 receives a stop signal for the drain pump 7, it transmits this to the relief valve 10 and the control valve 11, and changes the opening degrees of these valves. At the same time, this signal is also transmitted to the standby machine of the low-pressure condensate pump 2 and the first condensate stop valve 15, respectively, to start up the standby machine and control the valve opening of the first condensate stop valve 15 at the same time. It is a position. On the other hand, the control device 19 sets the valve opening degree of the second condensate stop valve 16 to the fully open position when the condensate flow rate detected by the flow meter 17 exceeds a predetermined value.

The present invention has the above configuration, and when one of the drain pumps 7 stops abnormally, a signal is issued to open the relief valve 10, and a part of the feed water heater drain from the drain tank 6 is transferred to the condenser 1. This prevents the water level in the drain tank 6 from becoming too high. At the same time, the valve opening of the control valve 11 is throttled to reduce the feed water heater drain flowing into the condensate system, and the amount of condensate decreases accordingly, but a stop signal from the drain pump 7 causes the low pressure condensate pump 2 to A signal is issued to start the pre-equipment, ensuring the amount of condensate necessary to maintain turbine output. Due to the increase in the amount of condensate passing through the condensate system, the condensate purification device 3 will run out of capacity. Since a signal to open the water stop valve 15 is also issued, some of the condensate is guided to the emergency condensate purification device 14, where it is purified and then returned to the condensate on the downstream side of the condensate purification device 3. sent to. As a result, even if the capacity of the condensate purification device 3 is the same as before, there will be no problem in maintaining the turbine output, and on the other hand, since the condensate is purified by the emergency purification device 14, there is no worry that the water quality will deteriorate. . The capacity of the emergency purifier 14 is determined based on the discharge port of one drain pump 7, but the capacity does not need to be that large. For this purpose, the flow rate after the condensate joins on the downstream side of the condensate purification device e13 is monitored by a flow meter 17, and even if the condensate purification device 3 and the emergency purification device 14 are combined in terms of capacity, If there is insufficient water, unpurified condensate is used to cover the shortage, thereby suppressing the increase in capacity. That is, when the condensate flow rate exceeds a predetermined value, a signal is generated to open the second condensate stop valve 16 provided in the second bypass pipe 13, so that the condensate flow rate exceeds a predetermined value. A flow of condensate with the lowest flow rate is formed that bypasses both the purification device 3 and the emergency condensate purification device M14, thereby ensuring the necessary amount of condensate at all times.

[Effects of the Invention] As described above, the present invention provides first and second condensate stop valves that are branched from the upstream side of the condensate purification device in the condensate system and reach the downstream side of the condensate purification device. Since the first and second bypass pipes are provided, and an emergency condensate purification device is placed in the path of the first bypass pipe, the turbine output can be maintained in the event of an abnormal stop of the drain pump. Moreover, it has the excellent effect of preventing the quality of water supply from deteriorating.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an example of a turbine plant using the feedwater heater drain injection device according to the present invention, and FIG. 2 is a system diagram showing an example of a turbine plant having the feedwater heater drain injection device according to the prior art. be. 1... Condenser 3... Condensate purification device 5...
......Feed water heater drain injection device 6...
・・・・・・Drain tank 7・・・・・・・・・・・・
・Drain pump 8...Drain purifier 10...Relief valve 12...First Bypass pipe 13・
......Second bypass pipe 14...
......Emergency condensate purification device 15...
......First condensate stop valve 16...
...Second condensate stop valve 17...
Flow hanging meter 18.19... Control tIl device

Claims (1)

[Claims] Drain generated by heat exchange with condensate in a low-pressure feedwater heater is collected into a drain tank, and this drain is injected into the condensate flowing through the condensate system via a drain pump. In a turbine plant having a feedwater heater drain injection device configured to release drain from the drain tank to a condenser, the system is branched from an upstream side of a condensate purification device in the condensate system and downstream of the condensate purification device. providing first and second bypass pipes each having first and second condensate stop valves, further disposing an emergency condensate purification device in the path of the first bypass pipe,
As a result, in the event of an abnormal stop of the drain pump, almost the entire amount of increasing condensate is purified through the emergency condensate purification, and the remaining part is directly guided into the condensate without being purified. A turbine plant having a featured feedwater heater drain injection device.